Scientists Demo Long Cycle-Life Lithium-Sulfur Battery

Department of Energy researchers have demonstrated in the laboratory a battery that has twice the specific energy of lithium-ion batteries. The Lawrence Berkeley National Laboratory has demonstrated a lithium-sulfur (Li/S) battery that lasts for more than 1,500 cycles of charge-discharge with minimal decay of the battery’s capacity. This is longest cycle life reported so far for any lithium-sulfur battery.

New battery chemistries that could deliver more power and energy than lithium-ion batteries are the driving force behind high-performance batteries for electric and hybrid electric vehicles. Lithium-ion batteries are the best performing batteries in the marketplace but are incapable of matching the range and power of combustion engines.

For electric vehicles to have a 300-mile range, the battery should provide a cell-level specific energy of 350 to 400 Watt-hours/kilogram (Wh/kg). This would require almost double the specific energy (about 200 Wh/kg) of current lithium-ion batteries. The batteries would also need to have at least 1,000, and preferably 1,500 charge-discharge cycles without showing a noticeable power or energy storage capacity loss.

The cells may lead to the development of zero-emission vehicles with a driving range similar to that of gasoline vehicles. The results were reported in the journal Nano Letters.

Lithium-sulfur battery chemistry has attracted attention because it has a much higher theoretical specific energy than lithium-ion batteries. Sulfur is nontoxic, safe and inexpensive, which adds to its appeal.

The battery initially showed an estimated cell-specific energy of more than 500 Wh/kg and it maintained it at >300 Wh/kg after 1,000 cycles—much higher than that of currently available lithium-ion cells, which currently average about 200 Wh/kg.